Direct

Direct lights emit parallel light in one direction and appear to illuminate all objects with equal intensity, as if it was coming from a far away source - you can use direct light to simulate sunlight and moonlight, for example. Being at an infinite distance from the objects, direct light has orientation, but no position. To generate accurate shadows from a Direct light, view the scene through the light (using the Viewer's camera dropdown menu, just like a camera) and adjust the Direct light's scale control so that the part of the scene that should cast shadows fits within the view. This ensures that none of the shadow-casting geometry is missed by the depth map.

See also Light, Spot, Point, Environment, and Relight.

Inputs and Controls

Connection Type	Connection Name	Function
Input	unnamed	An Axis, a Camera, or another Light node.

Control (UI)	Knob (Scripting)	Default Value	Function
DirectLight Tab
color	color	1	Sets the color of the light.
intensity	intensity	1	Sets the brightness of the light.
display	display	wireframe	Adjusts the display characteristics of the 3D object. These settings don’t affect the render output of the scene; these are for display purposes only in the 3D Viewer. • off - hides the 3D geometry object. • wireframe - displays only the outlines of the object’s geometry. • solid - displays all geometry with a solid color. • solid+lines - displays the geometry as solid color with the object’s geometry outlines. • textured - displays only the surface texture. • textured+lines - displays the wireframe plus the surface texture.
selectable	selectable	enabled	When enabled, you can make selections as normal in the Viewer. When disabled, points cannot be selected or changed.
	file_menu	N/A	Select to import or export a channel file: • Import chan file - import a channel file and transform the object according to the transformation data in the channel file. Channel files contain a set of cartesian coordinates for every frame of animation in a given shot. You can create and export them using Nuke or 3D tracking software, such as 3D-Equalizer, Maya, or Boujou. • Export chan file - export the translation parameters that you’ve applied to the object as a channel file. This is a useful method of sharing setups between artists.
	snap_menu	N/A	• Match selection position - the object is snapped to a new position depending on the points selected. • Match selection position, orientation - the object is snapped to a new position and orientation depending on the points selected. • Match selection position, orientation, size - the object is snapped to a new position, orientation, and size depending on the points selected.
transform order	xform_order	SRT	Sets the operation order for scale (S), rotation (R), and translation (T). The possible operation combinations are SRT, STR, RST, RTS, TSR, TRS.
rotation order	rot_order	ZXY	Sets the order of rotation. The possible axial combinations are ZXY, XYZ, XZY, YXZ, YZX, ZXY, ZYX.
translate	translate	0, 0, 0	Lets you translate the object along the x, y, and z axes. You can also adjust translate values by clicking and dragging the object in the 3D Viewer.
rotate	rotate	0, 0, 0	Lets you rotate the object around the x, y, and z axes. You can adjust rotate values by holding down Ctrl/Cmd and dragging in the 3D Viewer.
scale	scaling	1, 1, 1	Lets you scale the object on the x, y, and z axes.
uniform scale	uniform_scale	1	Lets you scale the object simultaneously on the x, y, and z axes.
skew	skew	0, 0, 0	Lets you skew the object on the x, y, and z axes.
pivot	pivot	0, 0, 0	When you make changes to a 3D object’s position, scaling, skewing, and rotation, these occur from the location of the object’s origin point or pivot. The pivot x, y, and z controls allow you to offset the pivot point and move it anywhere you like - you can even move it outside of the object. Subsequent transformations applied will then occur relative to the new pivot point location. You can also hold down Ctrl/Cmd+Alt and drag the pivot point to a new location in the 3D Viewer.
Local Matrix
specify matrix	useMatrix	N/A	Enable this control to specify matrix values for the object you’re transforming as an alternative to setting transform, scale, skew and pivot values above.
matrix	matrix	N/A	The matrix displays values from the object’s transform, rotate, scale, skew, and pivot controls. Check specify matrix and copy or drag-and-drop matrix values from another object to apply those values, for example, if you wanted to align objects in a scene.
World Matrix
matrix	matrix	N/A	Displays the world or absolute xyz transform of the node in world coordinates. Note: Unlike the Local matrix, you can’t adjust the World matrix manually.
Shadows Tab
cast shadows	cast_shadows	disabled	When enabled, the light casts shadows as defined by the Shadow controls.
shadow mode	shadow_mode	solid	Presents three shadow casting modes that affect shadows cast by objects, based on the objects’ opacity: • solid - objects that cast shadows are considered to be completely solid. This option can be used with both ScanlineRender and PrmanRender. • clipped alpha - objects that cast shadows are considered to be transparent if the object’s alpha is below the light’s clipping threshold control in the Shadows tab. This option is only relevant if you are using ScanlineRender to render your shadows. • full alpha - shadows are calculated based on how light is reduced when it passes through non-opaque occluders. This option is only relevant if you are using ScanlineRender to render your shadows.
filter	filter	cubic	Determines the type of filter that the shadow mode uses when it’s set to clipped alpha or full alpha.
scene epsilon	scene_epsilon	0.001	An offset that moves the sampling point away from the geometry surface, towards the light that is casting the shadow. Increasing this value can reduce self-shadowing artifacts. This control is only relevant if your shadows are generated using depth mapping and shadow mode is set to full alpha.
samples	samples	1	Sets the number of samples for the light when generating soft shadows. If soft shadows in your scene appear dotty or noisy, try increasing this value. The higher the value, the smoother the soft the shadows become. This control is only relevant when shadow mode is set to solid or clipped alpha.
sample width	sample_width	1	Sets the size of the light for soft shadows. This value determines the width of the soft area around the egde of a shadow. The higher the value, the larger the soft area. This control is only relevant if your shadows are generated using raytracing.
bias	depthmap_bias	0.01	Sets the bias for the raytracing or shadow map. Increase this value if self shadowing artifacts appear in the image. This moves the surface sample point away from surface. Note, however, that if you increase the value too much, some shadows may start moving away from the base of the objects that cast them. This control is only relevant when shadow mode is set to solid or clipped alpha.
slope bias	depthmap_slope_ bias	0.01	Bias for the shadow map. This is like bias, but the offset is proportional to the slope of the depth map. This allows you to give a different offset to each value in the depth map, depending on the surface’s slope relative to the light. If increasing bias reduced the existing self-shadowing artifacts but introduced more artifacts in other areas of the image, you may want to bring bias down a little and increase slope bias instead. This control is only relevant if your shadows are generated using depth mapping and shadow mode is set to solid or clipped alpha.
clipping threshold	clipping_threshold	0.5	Objects that are set to cast shadows are considered transparent if their alpha is below the value set here. This control is only relevant if your shadows are generated using depth mapping and shadow mode is set to clipped alpha.
jitter scale	shadow_jitter_scale	3	Sets the amount of jitter used when doing percentage-closer filtering (PCF) for soft shadows. A larger jitter scale value results in softer, more perceptually accurate shadows. PCF works by sampling the depth map at many different positions around the same spot. The final shadow value for that spot is an average of how many of the samples were occluded or visible from point of view of the light. This control is only relevant if your shadows are generated using depth mapping and shadow mode is set to solid or clipped alpha.
depthmap resolution	depthmap_width	1024	Sets the resolution of the depth map. Larger values will result in a less crunchy edge, but will require more time to process. Note that you can also fix crunchy edges by increasing the number of samples instead of increasing the depth map resolution. This control is only relevant if your shadows are generated using depth mapping and shadow mode is set to solid or clipped alpha.
output mask	shadow_mask	disabled	Enables the associated channel to the right. Disabling this checkbox is the same as setting the channel to none.
output mask	shadow_mask	none	Sets the channel you want to output the shadow map into. This can be enabled even if the cast shadows box is disabled.

Step-by-Step Guides

Working with Lights

Video Tutorials

3D Workspace Overview - Step Up to Nuke Tutorial 11

3D Workspace Overview from Foundry on Vimeo.

Transcription

Nuke is not limited to a 2D space, in fact, it has a complete 3D environment built right in. For example, here is a 3D ship and a 3D sphere. In order to see the 3D environment, go to the View menu where it says 2D and switch that to 3D, and there’s the environment. In order to change the view, which is the default camera, you can use the Alt or your Option key, along with your mouse buttons. For example, Alt and left mouse button scrolls, Alt and middle mouse button zooms, and Alt and right mouse button orbits.

Let’s see what we have in the scene. There is a 3D Camera, a Spotlight, a Point light, a primitive Sphere, an imported spaceship, and a large primitive Card in the background. Let’s take a look at the node network, and you can see what we need to make a 3D scene happen. The node with the most connections is the Scene node. The Scene node groups together lights and geometry in order to pass them on to a render node. In order to render the scene so it becomes 2D, you need to have some sort of render node. In this case, there is a ScanlineRender node. Connected to the ScanlineRender is a 3D Camera. Connected to the Scene node are two lights - there is the Spotlight and the Point light. If I open up the properties on the Spotlight, you can see common options like color and intensity and, in the case of the Spotlight, cone angle. There are also two pieces of primitive geometry here - there is the Sphere and the Card. This will be a good time to note that 3D nodes have a rounded, pill-like shape, as opposed to the rectangular 2D nodes.

You can create a light or a primitive piece of geometry through the 3D menu. You can make your Point or your Spot, plus a Direct and a few specialized lights, like the one that’s called Light, which you can use to import lights from other programs, like Maya. There is also the Geometry menu, which has the primitives such as Card, or other shapes, like Cube and Cylinder. You can transform lights and geometry. For example, if I open up the Sphere, you will see there is a translate, rotate, and scale property. Once this is open, you will also see there is a transform handle. If you click+drag the handle along the axis, you can move it in that direction, for example, Y. Of course, you can also enter values into the properties panel. Lights also have their own set of transforms. Now, one new feature is the fact that lights can cast shadows right here in the 3D environment. For example, if I go to the Spotlight and go to the Shadows tab, you will see there is a place to click on cast shadows. Let’s go back to the 2D view. You can see the shadow of the Sphere right here on the spaceship. Now, aside from shadows of course, you can animate all of these properties. You can animate the light, changing over time, as well as the geometry. There are also animation buttons beside all of these properties. You can key these as you would any other node inside Nuke.

You will notice that the two pieces of geometry have shaders connected to their img pipes. These are necessary for the surfaces to be lit correctly. The Sphere has a Phong, which is similar to the one you might have in a program like Maya. The Card has an Emission shader, which has the emissive component or the ambient color component. Now, in terms of the spaceship, it has to be imported through a ReadGeo node. ReadGeo node has a place to bring in the file, and this supports .fbx files, or .obj files, or alembic files, .abc. If there is animation in the file, Nuke will recognize it. For example, with the .fbx file, it might have multiple takes. Nuke will recognize that and you can choose the animation take. So, if I go back to the 3D view, scrub the timeline, and we will see the ship is pre-animated, and this animation was created in Maya. There is also a material connected to the img pipe of the ReadGeo. Now, because the UV texture space came through the .fbx file, in order to map the geometry, you just need to bring in the texture bitmaps through Read nodes, and connect to a shader. For example, here is the diffuse map connected through the mapD, or map diffuse. There is a specular map connected through the mapS, or map specular. Lets go back to the 2D view.

Now, if anything is animated, you can also activate motion blur. To do that, you go to the render node and, for example, with the ScanlineRender, go to the MultiSample tab and change samples to a higher number like 8. At that point, the motion blur will appear, as you can see right here. The higher the samples number, the higher the quality.

So, there is a brief introduction to Nuke’s 3D environment. Keep in mind that any node you need to create for this you can find through the 3D node menu. This includes all your shaders, geometry, lights, Scene nodes, and cameras. Aside from animating lights and geometry, you are also free to animate cameras. They have their own set of transforms. In any case, I would suggest exploring this component of Nuke.